Alternative methods to synthetic chemical control of Cynodon dactylon (L.) Pers. A systematic review

Abstract

Cynodon dactylon (L.) Pers. is one of the worst agricultural weeds and invasive species in the world, being widely established in many countries. Despite its impact on agriculture and the growing awareness of authorities and consumers about the consequences of synthetic herbicides, alternative control methods for this weed have been poorly reviewed. A systematic review of the literature published over the last 50 years was used to assess the most studied control methods of C. dactylon (excluding synthetic herbicides) and to summarize the trends and knowledge gaps. The major findings are as follows: (1) the number of publications that studied alternative methods to synthetic chemical control in C. dactylon management has been increasing exponentially since 1972; (2) most of the studies were made under controlled conditions (57%) and lack observations under real production conditions; (3) most of the field experiments were carried out in Asia (42%), under temperate subtropical and arid climates; (4) the publication of articles studying allelopathy stands out significantly (50% of the papers found), with two species from the Poaceae family, rice (Oryza sativa L.) and sorghum (Sorghum bicolor (L.) Moench), showing very high allelopathic inhibitory effects (often above 80%), especially under open field conditions; and (5) preventive soil tillage is the most studied treatment among indirect weed control treatments, and although there is a high risk of propagation, the results indicate that tillage can significantly contribute to control C. dactylon, when compared to no-tillage treatments. Further research is needed to optimize treatments and methods so that they can be applied by farmers under real production conditions.

Imperatives for integrated weed management in vegetable production: Evaluating research and adoption

“…It is also labor‐intensive and very costly, and therefore not practical as a standalone or primary method of weed control (Pannacci et al, 2017). Effectiveness can also depend on weed species present; for example, hand weeding is likely to be less successful in the case of species that are capable of re‐establishing from plant fragments (Peerzada, 2017; Soares et al, 2023).…”

“…Some hand weeding and chemical or mechanical control is still likely to be required to manage weeds between the crop rows, or in crop planting holes in the mulch film (Brown & Gallandt, 2019). Organic mulch options (e.g., cover crop residues, sawdust, wood chips, straw or sugarcane by‐products and paper waste) can suppress weed growth with mixed levels of success, though are generally considered less effective than plastic mulch film (Campiglia et al, 2010; Kristiansen et al, 2015; Olsen & Gounder, 2001; Reberg‐Horton et al, 2012; Soares et al, 2023).…”

Root cutters: Novel tillage methods to control creeping perennial weeds with a low risk of soil erosion and nutrient leaching

“…The main alternatives to herbicides to control perennial weeds are using a combination of preventive measures (e.g. the inclusion of regularly mown competitive leys or cover crops, which can be effective against some perennial weed species (Thomsen et al 2015)) and/or using intensive tillage (e.g., multiple harrowing operations to fragment the roots/rhizomes followed by moldboard plowing) (Ringselle et al 2020; Soares et al 2023). An increased use of preventive measures would be bene cial to agricultural sustainability and create more diverse cropping systems which do not promote a few highly competitive weed species like monocultures do (Adeux et al 2019).…”